Seems, like it is hard to post something from a new account, so I will try agian.
I downloaded Starred mu client three times [twice from google (full and lite), once .. somewhere else]. Each time when unpacking my antivirus, G data total security, with updated database, found this: Variant.Ursu.888188 in a game.exe file. The same happened when I tried launching game .. altho it tried to acces some .dll files from windows folder.
I downloaded some other private server client, and even official client to swich the file (but there was no such a file at all). With those two, g data did not find anything suspicious.
Imo it is some ransomware or keylogger - it makes sense why server does not have a we shop.